Fifteen hundred cubic inches, or twenty-two quarts, of carbonic acid are
expired from the lungs every hour, and thrown off into the surrounding
atmosphere. Besides this, Sequin found that 18 grains of organized matter
were thrown off per minute from the body in the form of insensible
perspiration,--7 grains by the lungs, and 11 grains by the skin. Hence we
may form some idea of the rapid corruption of the air in this stockade,
where 30,000 men were breathing at one time. The foul and heavy vapors
could not rise above the palisades unless a strong breeze prevailed; and
even then they became so offensive as almost to extinguish life, like the
deadly air of the Grotta del Cane. The exhalations from putrescent animal
surfaces are always specifically heavier than the upper warm strata in the
confined spaces where men are crowded together, such as the wards of
hospitals. We find, according to Professor Graham, the vitiated air to be
composed somewhat as follows: Phosphoretted hydrogen, sulphuretted
hydrogen, carbonic acid, carburetted hydrogen, cyanogen with its
compounds. The first gas is always recognized where the diseases of the
internal organs are present, especially affections of the liver, stomach,
bowels, and in fever and dysentery; and we observe the blackening of the
lead plaster, &c., when the second is present. Stupor, headache, and
sleepiness betray the presence of the other three gases. The diffusion of
each gas is always inversely as the square root of the density of such
gases.